(中南大学 资源加工与生物工程学院，长沙410083)
摘 要: 自云南酸性热泉水样中分离出一株中度嗜热硫氧化菌YN12。对其形态特征和生理生化特性以及16S rDNA序列分析结果证明，该菌株归属于喜温嗜酸硫杆菌(Acidithiobacillus caldus)。重金属抗性实验表明，YN12菌株对3CdSO4∙8H2O具有超强抗性，其最高初始Cd2+耐受浓度达4.8 g/L。在此基础上，不断提升3CdSO4∙8H2O浓度，其最终Cd2+耐受浓度可达31.5 g /L(相当于3CdSO4∙8H2O 210 g/L)。在该最终Cd2+耐受浓度下，经过连续3代的适应性生长，YN12菌株的生长速度和硫氧化活性均能得到较好的恢复。
关键字: 喜温嗜酸硫杆菌；YN12菌株；镉抗性；最高耐受浓度
（School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:A moderately thermophilic sulfur-oxidizing strain, YN12, was isolated from an acidic hot spring sample collected in Yunnan Province, southeastern China. Morphological, physiological and 16S rDNA sequence data suggest that YN12 belongs to the species, Acidithiobacillus caldus. YN12 exhibits a very high degree of resistance to cadmium (Ⅱ), with an original maximum tolerated concentration (MTC) of 4.8 g/L and an ultimate MTC of 31.5 g/L after adapted by a gradually increased concentration of 3CdSO4∙8H2O. Continuously cultured in the medium containing 210 g 3CdSO4∙8H2O/L (equal to 31.5 g/L of Cd2+) for three generations, the strain is capable of restoring its growth and sulfur oxidation activity to an approximately normal level.
Key words: Acidithiobacillus caldus; strain YN12; cadmium resistance; maximum tolerated concentration
